OBJECTIVES: To investigate the mechanism of action of pancreatic cholesterol esterase in the total process of cholesterol absorption and to search for means of inhibiting cholesterol absorption. Investigation regulatory mechanisms for the synthesis and hydrolysis of cholesterol esters in other tissues, i.e. aorta, adrenal, and ovaries. RESEARCH GOALS FOR THE PERIOD: A. Further scaling up of procedures for preparation of cholesterol esterase from pancreas and other tissues. B. Determination of cross-reactivity of low-energy cholesterol esterases in tissues such as liver, aorta, and adrenals. C. Localization of cholesterol esterase in intestinal mucosa. D. Completion of studies in the mechanism of activation of adrenal cholesterol ester hydrolase. E. Continuation of studies on activation of cholesterol ester hydrolase in the adrenal and in ovaries. F. Continuation of studies in isolated intestinal cells in respect to cholesterol and fatty acid uptake, the formation of lipoproteins in these cells, and release of these lipoproteins into the media. BIBLIOGRAPHIC REFERENCES: Purification and Properties of Subunits of Sterol ester hydrolase from Rat Pancreas. K.B. Calame, L. Gallo, E. Cheriathundam, G.V. Vahouny, and C.R. Treadwell. Arch. Biochem. Biophys., 168, 57, (1975). Activation of Adrenal Sterol Ester Hydrolase by Dibutyryl cAMP and Protein Kinase. Soraya Naghshineh, C.R. Treadwell, L. Gallo, and George V. Vahouny. Biochem. Biophys. Res. Comm., 61, 1076, (1974).